Life-Cycle Impacts of Transit-Oriented Development

There is a growing interest in pedestrian and transit-oriented development as a way to reduce the cost of transportation and home energy use. Yet there is little knowledge of how much alternative travel modes and compact developments reduce environmental impacts and household costs. As US cities begin to rethink their growth, city planners need better tools to measure the environmental and economic effects of infrastructure redesign. We have developed a life-cycle assessment framework that helps planners understand how energy use, air pollution, and household costs change when integrating transportation and land use planning around high-capacity transit. Using this framework, we can evaluate emissions from the construction and rehabilitation of buildings around transit, changes in household energy use within these neighborhoods, and reductions in automobile use as households shift some of their travel to alternate modes. We compare transit-oriented households to households that do not have access to high-capacity transit. Using Los Angeles’s Gold Line (light rail) and Orange Line (bus rapid transit) as case studies, we assess how these variables changed with development around those lines.

The Los Angeles County Metropolitan Transportation Authority (LA Metro) operates one of the largest urban bus systems in the United States, in addition to a growing number of high-capacity bus and rail lines. The LA Metro system of high-capacity transit (HCT) comprises six rail lines and two bus-rapid-transit lines that run on dedicated routes, have short wait times, and carry large numbers of passengers. In addition, LA Metro plans to spend $14 billion to expand HCT lines. The growth of physical infrastructure has been accompanied by impressive ridership increases on all HCT lines, as many residents—particularly those living near transit stations—have chosen to change their travel habits and adopt transit